Writing documentation for the equivalent of 8th graders is pretty common for any writing, so I made a habit of doing that a long time ago. It's like coding - if you're too clever, it's hard to understand and read later.

How hard is it to really use reasonable font sizes and contrast ratios? How hard is it to add a few more tags to your site? How hard is it to caption videos as you're making them (most time you're working from a script anyways).

If you're not starting these good practices from the beginning, yes, it will be harder to do all at once later. But if you start doing it from the beginning, it is pretty easy to do. Just like testing. Just like coding standards. Just like design patterns.

It's easy to accuse people of pointing fingers and judging people, too, and genuinely difficult to make high-quality, thought-provoking Hacker News postings.

(Your comment would have been much better had you left out the rude accusations.)